With no obvious headline on Day 7 at the US Open, David and Catherine start the Tennis Podcast by purring over the form of Sloane Stephens and trying to pin down what makes her such a sublime player. They agree she has a sixth sense, but is she unstoppable at her best? It certainly felt like it against Elise Mertens.  Another good performance from Serena is discussed. How well did she do to weather the second set onslaught from Kaia Kanepi? Will the quietly impressive Karolina Pliskova provide her biggest test yet in the next round?Dominic Thiem pulled off the result of the day on the men’s side, beating last year’s finalist Kevin Anderson in straight sets. Did Anderson’s five-setters catch up with him?Thiem’s next opponent is Nadal. The world No.1 was rattled by the brilliance of Basilashvili, with the Georgian adopting a similar aggressive approach to Khachanov. Has Khachanov softened Nadal up? If so, can Thiem deliver the knockout blow?Elsewhere, John Isner and Milos Raonic played a five-set match without any tiebreaks. How on earth did that happen?On Monday, Maria Sharapova has been handed another night session slot. That’s four in a row. Is that fair?There will daily editions of The Tennis Podcast throughout the US Open fortnight. The Tennis Podcast is produced in association with the Telegraph and sponsored by Amazon Prime Video, the new home of the US Open in the UK.  See acast.com/privacy for privacy and opt-out information.